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Understanding BIP-420: A Step Towards Bitcoin’s Evolution
Understanding BIP-420: A Step Towards Bitcoin’s Evolution
Understanding BIP-420: A Step Towards Bitcoin’s Evolution

Raise your hand if you know what OP_CAT and BIP-420 are? Almost no one? Good—I can tell this is an Ethereum crowd. In all seriousness, there’s some cool innovation happening in Bitcoin land that’s worth reviewing. Our story starts all the way back in 2010 - that’s like a century in crypto time!

A Bit of History

Shortly after the founding of Bitcoin, there existed an OP code called OP_CAT, which would allow anyone to build smart contract-type functionality on Bitcoin. While this proposal generated a lot of discussion and excitement, it was ultimately removed due to security risks (DDoS attacks) by none other than Satoshi Nakamoto, and has been shelved away ever since.

The Revival: BIP-420

Now over a decade later, the Bitcoin ecosystem looks much different. Innovations such as Ordinals, BRC-20 tokens and the Taproot upgrade have opened up new possibilities for the network and resurged interest in OP_Cat, which is now being called BIP-420.

The BIP-420 proposal aims to reintroduce the OP_CAT code through a proposed soft fork. It allows the combination of two stack elements into one, enabling more complex Bitcoin scripting capabilities akin to basic smart contract functionality.

With OP_CAT, Bitcoin can start building Layer 2 solutions and more complex scripts, such as secure vaults and decentralized key exchanges. This enhanced functionality could significantly broaden Bitcoin’s use cases, and bring it a step closer to Ethereum’s smart contract capabilities.

Starkware’s Contribution

Starkware recently announced that once OP_CAT is implemented, they will have a path to introducing STARKS to the Bitcoin ecosystem, creating a unified Layer 2 across EVM and Bitcoin. To accelerate this, they are sponsoring $1M in research to explore the pros and cons of OP_CAT. This sponsorship underscores the potential impact and importance of BIP-420 in the Bitcoin and overall crypto landscape.

Dynamic’s Contribution

At Dynamic, we are thrilled about the potential that BIP-420 brings to the Bitcoin ecosystem. We are committed to contributing to this evolving landscape through innovative projects like BitcoinKit. BitcoinKit is designed to empower developers with the tools needed to build sophisticated applications on the Bitcoin network, leveraging the advancements that proposals like BIP-420 offer.


In summary, BIP-420 has the potential to unlock serious innovation within the Bitcoin ecosystem. While adoption might take time—considering the stakes involved in Bitcoin—it’s clear that this proposal could lead to significant advancements and new possibilities for the grandfather of crypto. I wouldn’t be surprised to see more companies and initiatives emerge if this OP code gets closer to reality.

For more details, check out these resources:

Starkware: Scaling Bitcoin for Mass Use

GitHub: BIP-420

Crypto News Flash: Bitcoin’s Protocol Evolution


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Itai Turbahn

Itai is the co-founder and CEO of Dynamic. Before Dynamic, Itai spent 7 years in product management leadership positions, and was previously a consultant at the Boston Consulting Group. Itai holds an MBA from Harvard Business School and B.Sc degrees in EECS and Economics from MIT.

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